Bookings are essential (max. 30
walkers) Contact the
Blaauwberg Conservation Area on
the 021 554 0957 or e-mail us on
bca@capetown.gov.za

HACK

This all important work of
removing alien vegetation must
continue year in and year out
and we call on all members to
lend a hand!

Date: Saturday 22 May Time:
08h00 to 10h30 Meet: at the gate
to the Model Aircraft field on
the R27.

For all queries please contact
Nelis VIsagie on 082 777 5708.

DIEP RIVER ESTUARY MANAGEMENT PLAN

In our previous newsletter we listed the various
projects that have been initiated. There are already
some interesting preliminary results coming out of
some of the short-term investigations and we will
report on this as soon as these projects have been
finalised. An official request has been submitted to
the City for funds for implementing the very
important hydrology and geohydrology project – this
project is to study the dynamics of water flow and
sediments in the system and is vital to provide us
with an understanding of how the system works.

DIEP RIVER / FYNBOS CORRIDOR PROJECT

Christopher Singo is the new Site Officer, appointed
by the City of Cape Town, for the Diep River/Fynbos
corridor area. He and Henk Louw are working together
to manage this important area. Christopher was
previously a conservator at Table Mountain National
Park. Christopher is a valuable addition to the
conservation staff in the area, and we welcome and
support him in this important work. We have also
supplied Henk Louw with a pair of binoculars and a
camera for his field work. Quick observations, and
the recording of them, are essential for both law
enforcement and recording species and events.

New People In and Around Rietvlei

Rifqah Johnson started as Environmental Education
intern at Rietvlei in March and has already been
very active in getting groups of learners to attend
courses at the Educational Centre.

Proposals for development of the Gold Circle stable
properties at Milnerton Racecourse.

In our February newsletter we reported about our
concerns with shortcomings in the Draft Basic
Assessment Report for the proposed mixed-use
development at the Gold Circle Stables on Koeberg
Road. Since then a formal application for the
rezoning has been submitted to the City, even though
the Final Basic Assessment report has not yet been
submitted to Province.

We objected to this rezoning application on the
grounds that the application was premature, and also
that the existing layout was not acceptable. Our
concerns with the draft report was the basis for our
objection and were added to our submission to the
City.

Expansion and Upgrading of Wastewater Treatment
Infrastructure in the Blaauwberg Area.

There have been various behind-the-scenes
developments taking place with respect to the
proposals for this expansion and upgrading. At this
stage we are not in a position to report on the
situation, but you can be assured that your
committee is keeping a close eye on these
developments to ensure that our interests, and those
of Rietvlei and the environment, are given due
consideration.

Light Pollution at Rietvlei

We were horrified to see the row
of lamp poles being erected
along the R27 on the western
boundary side of Rietvlei. The
visual impact is severe between
Sunset Beach and Dolphin Beach,
particularly on that side where
the horizon is low and there are
no high buildings or other
developments to spoil the view.
Although there is continuous
traffic along the R27, this
traffic is on a low level and is
not so obtrusive.

However, apart from the visual
pollution caused by this row of
lights, we are very concerned
about the effect on the
environment of this high level
lighting. We discovered that in
the original environmental
impact study for the IRT, the
possible effects of light
pollution had not been included
in the report. This is in spite
of the fact that there is a
considerable amount of published
literature available on light
pollution.

Light pollution has negative
effects on plant and animal
physiology – it confuses animal
navigation, alters competitive
interactions, changes
predator-prey relations, and can
cause physiological harm. The
rhythm of life is orchestrated
by the natural diurnal patterns
of light and dark, disruption of
this pattern impacts on
ecological dynamics. The effect
of light pollution on natural
ecosystems was first studied in
1938, but it is only in the last
10 years that substantial
research in this field has been
undertaken. A wide range of
consequences of light pollution
has emerged in this research.

A few examples that may apply to
Rietvlei are briefly related
here, but keep in mind that the
high level lighting along the
R27 could have more effects.

It has been shown that lights
around lakes and wetlands
prevent zooplankton from rising
to the surface and feeding on
surface algae at night. This can
contribute to algal blooms which
lowers water quality. Artificial
light at night also interferes
with the ability of moths and
other nocturnal insects to
navigate, which in turn could
negatively affect
night-flowering plants dependent
on moths for pollination. Lights
at night can also interfere with
the breeding activities and
reproductive cycles of frogs and
toads – in many species these
cycles are cued by moonlight and
constant artificial light
confuses the animals.

Migrating birds are often
disrupted by high level
artificial lighting – in some
parts of Canada there is a
programme whereby lights on tall
structures are turned off during
bird migration periods. In the
North Sea researchers are
experimenting with new lighting
technologies to reduce the
effect of offshore oil and gas
platforms on the migration
routes of birds. Some birds fly
around only at night and could
be discouraged from such flights
by excessive night lighting, a
local example is the African
coot who fly in considerable
numbers between water bodies at
night – we don’t know what the
effect of more night lighting
would be on birds like these in
Rietvlei.

Studies have also shown that
night lighting can have severe
effects on insectivorous birds
feeding at dawn and dusk as the
insects they feed on are
attracted to artificial lights
whereas the feeding birds mostly
avoid lights. The same applies
to bats feeding at night as they
also tend to avoid lights while
their prey is attracted to
lights. Further, large numbers
of these prey species die at
these lights each night, this
leads to a decline in the prey
population which also negatively
affects the populations of
insectivorous birds and bats.

These few examples illustrate
that night lighting can have
far-reaching effects on the
natural environment. We do not
know what the effects of the
newly erected high level
lighting on the R27 will be on
Rietvlei, but from research done
elsewhere in the world we do
know that it is most likely
negative. The lighting on Otto
du Plessis Drive along the
estuary in Milnerton has very
likely impacted negatively on
the animal life in and along the
estuary over the years – but we
will probably never know exactly
what or how big this impact has
been.

The Friends of Rietvlei
submitted a brief report to the
City on this important issue. We
proposed that even at this late
stage it is necessary to
investigate in more detail the
effects of this lighting on
Rietvlei, and also to consider
ways and means by which negative
effects can be mitigated. We
realize that they may not remove
the lights, but steps such as
switching the lights off for a
period at night when the buses
are not operating should be
considered.

Energy Efficiency or Energy
Reduction

Energy efficiency has been
described as a renewable energy
resource that is perfectly
cheap, abundant and immediately
available. It can reduce carbon
emissions and reduce our
dependence on imported energy
resources. It does not pollute,
and it does not depend on the
weather like solar and wind
power. There are several ways of
improving energy efficiency in
your home – here is another tip:

You can save both water and electricity by reducing the amount of hot water you use in your kitchen sink or bathroom basin. This can easily be accomplished by using a small round plastic basin inside your sink and washbasin – there are various size basins that fit inside the sink or washbasin very nicely. With such a basin you can reduce the amount of water required by up to 50%.

Thanks go to Chevron Refinery for
sponsoring envelopes for the posted newsletter.